Our company has several Macs on the Active Directory Domain and a Blue Coat Proxy server. When the employees try accessing resources on the Internet, they get the following message when using Safari:
"Safari can't verify the identity of the website (Name of company's proxy)"
"The certificate for this website is invalid. You might be connecting to a website that is pretending to be "name of our company proxy", which could put your confidential information at. Would you like to connect to the website anyway?"
Employees accept/trust the certificate and are then prompted for their username and password to be able to view the site. After a few minutes to an hour, the same message reappears again. It comes with just about any website. Mozilla Firefox is experiencing something similar, "This connection is untrusted."
The Macs in the company use Snow Leopard, Lion, and Mountain Lion. Happens with all three Operating Systems.